CAIE IGCSE Biology 11.1.6 Internal & External Intercostal Muscles
Practise identifying internal and external intercostal muscles in diagrams of ribs and the thorax.
- Syllabus
- 2026–2028
- Course
- Biology 0610
Practise identifying internal and external intercostal muscles in diagrams of ribs and the thorax.
Fig. 1.1 is a diagram of the gas exchange system in humans.

Fig. 1.1
Draw a label line and the letter X on Fig. 1.1 to identify an external intercostal muscle.
correct label line with the label X to the external intercostal muscle ;